    class MyHashSet {
        public boolean[] arr;
        public MyHashSet() {
            arr=new boolean[100001];
        }

        public void add(int key) {
            arr[key]=true;
        }

        public void remove(int key) {
            arr[key]=false;
        }

        public boolean contains(int key) {
            return arr[key];
        }
    }